Determination effects of topping at different times on yield and yield components in cotton

This study was conducted to determine the effects of topping at different stages of growth on cotton in the Experimental Area of Faculty of Agriculture, Dicle University in 2012. In the study, cotton varieties were used as material such as Primera, Deltapine 499, Stoneville 453 and Berke (Gossypium hirsutum L.). Trial was established using the pattern of split plots design with 3 replications. Main plots are application times (control, 100, 115, 130 and 145 days after sowing); the sub-plot consisted of cotton varieties (Berke, STV 453, DP 499, Primera). It was determined in the study, topping times 100 and 115 days after sowing date increased such as seed cotton yield, per boll seed cotton weight, gin output; decreased the plant height and number of non-open bolls; had statistically no significant effect on characteristics such as 100 seed weight. Positive and significant correlations were determined between per boll seed cotton weight and seed cotton yield and gin output; the first hand seed cotton ratio and the number of non-open bolls and gin output. Negative and significant correlation were determined between plant height and per boll seed cotton weight; plant height and gin output